The invention relates to a change-speed gearbox, in particular for motor vehicles such as hybrid passenger cars or small trucks.
U.S. Pat. No. 5,715,727 discloses a change-speed gearbox which comprises an input shaft and two output shafts. Here, the input shaft can be connected to an engine by means of a clutch. The two output shafts engage with a drive output.
Furthermore, the change-speed gearbox in U.S. Pat. No. 5,715,727 has several gear wheel pairs in order to connect the first input shaft to one output shaft or to the other output shaft. Here, each gear wheel pair has one fixed wheel and one loose wheel. Each gear wheel pair is additionally assigned a gear shift clutch, by means of which the loose wheel of a gear wheel pair can be connected in a rotationally fixed manner to the shaft which bears the loose wheel. A torque is transmitted between the input shaft and the respective output shaft with a certain transmission ratio by means of the rotationally fixedly connected loose wheel, so that one forward gear is established per gear wheel pair.
In order to implement a reverse gear, the change-speed gearbox has a gearbox unit. The gearbox unit engages with that gear wheel pair which establishes a first forward gear of the change-speed gearbox. Here, the gearbox unit is responsible for the transmission of torque to a third output shaft which, like the other two output shafts, engages with the drive output.
If the change-speed gearbox in U.S. Pat. No. 5,715,727 is placed in reverse gear, the gear shift clutch which is assigned to the gear wheel pair of the first gear is simultaneously opened, so that the gear wheel pair of the first gear transmits the torque of the input shaft to the third output shaft without transmitting torque to the first or the second output shaft.
A number of gear wheels are arranged on the input shaft corresponding to the number of forward gears, the gear wheels arranged adjacent to one another on the input shaft significantly influencing the axial installation length of the change-speed gearbox. The axial installation length can be a critical variable in particular in an application in a motor vehicle on account of the small amount of space which is available there.